Under the iTunes in the Cloud section, click Manage Devices. (If you haven't associated any devices with your Apple ID, you won't see the Manage Devices section.) Information about each associated device appears. Next to each device, you can see when it associated with your Apple ID.
The real reason why the burp smells so badly is hydrogen sulfide (H2S). If you eat foods that have sulfur proteins in them then you may find yourself burping the H2S, which will smell like rotten eggs. The sulfur reducing microbes in the intestine digest the proteins and release the gas.
Quick Answer. According to a Mayo Clinic article appearing on CNN, burps that smell like rotten eggs are caused by hydrogen sulfide gas produced as food passes through the digestive system. Hydrogen sulfide in the gas can make it taste and smell like sulphur or rotten eggs.